New Owner - '97 Polaris SLT 780

Hi there fellas. Glad to be apart of this deal yall have going on here. Quite a bit of info I've browsed through in the past week has already been helpful, but I thought I'd try to fetch a little more. I'd rather ask questions and learn rather than be stubborn and screw it all up on my own lol!

Anyways, my buddy had this '97 Polaris SLT 780 w/ trailer sitting in his yard that he had told me he'd acquired for $1 (yes, one dollar!). He had previously had an auto/boat repair shop on our lake, and when they had to move on, the previous owner of the ski wasn't interested in having it fixed. He had damaged the front piston somehow. Long story short, my buddy had no interest in using it either, and the ski is in damn good shape, was very well maintained other than that one piston problem, so we agreed that if I put forth the $$$ to fix it, it was mine. 1 $60 piston and ring set, and top end gaskets, and I have myself a ski that runs like a top! Compression is great all the way through! I apologize before hand for all these questions, but here they come:

* I read that these older ski's should have the fuel system checked over and most likely have the lines and such replaced. They appear to be in great shape, although I don't know about the insides. The ski's been sitting for a year and a half until we fixed it and fired it, and test rode it this weekend, so is there anything else I should upgrade right off the top? Should I invest in new lines anyway??

* I'm aware that this ski came with a 15/20 swirl stock impeller. My buddy said he put a new impeller in it before the old owner ditched the effort, but he can't remember what it was. Can the numbers be taken from the impeller from the underside or somewhere without removing it?? I'm also a little bit stockier rider than most at 250 pounds. The "Dream-o-meter" topped out at 46.8 mph the other day on our lake in some pretty damn choppy water right before a storm. Is that about right for my size and those conditions? What can I expect in calmer water?? Should an impeller pitch change be in the forecast for me after other planned mods??

* I've read that my 3-seater already has a half decent ride plate underneath it (I'm assuming). Although reading that aftermarket plates are scarce for my ski, would an aftermarket ride plate such as the ocean pro be beneficial for me?? As far as my riding conditions, they'll most likely always be at our lake (Lake Anna, VA). It stays pretty choppy, but not too overly rough due to alot of recreational traffic, although if you go to the other side of the lake which I do sometimes, you might catch a calm day out of a few. Just depends on when I feel like alternating between the hot and cold sides of the lake.

* As far as intake grates, I'm reading that most of you are using an R&D or an Ocean pro for different reasons. I don't plan on being much of a trick rider or doing outrageous maneuvers with this thing, at least not anytime soon, and am really more-so concerned about getting as much speed out of this thing that I can. I drag race cars with most of my time, so what can i say, I'm addicted lol. To answer another question that may pop up, I'll rarely have anybody else on the ski with me, maybe a girl here or there , and the most that would happen would be pulling a smaller 1 person tube with a 90 pound kid on it, so that's the extent of it, mainly just me 95% of the time.

* I read a thread on the SBT forums about some people recommending changing the wedge to a 6 degree (I guess mine is 4 degrees??) and getting extended pumps. What the hell are they talking about, and what would I have right now?? What would you guys recommend???

* As far as gasoline, are most of you guys running 93 octane?? Is that whats recommended in these things??

* I think I'd like to change the reeds soon. Been looking at the Boyesen Pro Series reeds ( not the racing ones). Would this be a decent choice for what I'm looking for? (I don't see those V-Force's or the Boyesen Rad valves in my budget at this time lol).. If I put these reeds in, will I need to re-jet the carbs a huge amount?? If so, where can I acquire the needed jet kit for this?? Should I look into aftermarket reed cages if there are any?? Would the reed spacers be a good investment along with the other things??

* What is this "jetworks valve" that others have spoken of? Is it an upgrade and/or a necessity?

* I know they're pricey, but would the 785 Pro CDI be beneficial to me in the long run?? Does it require any major changes in the ski?

* Although I don't think I'm interested in the modifications (right now) required to install those "triple pipes" on this thing, I wouldn't mind having some kind of aftermarket exhaust. What are these "short pipes"?? Are they worth it, and if so, are they readily available anywhere??

*SIGH*

I think that's all I can think of right now. Like I said, I apologize for the length and any rambling. Just trying to learn and have some fun. Any links you guys could provide for anything I mentioned would be greatly appreciated. If you all need to know any more info from my end, that's no problem at all. I'm gonna try to provide some pictures of things as I go along, although my PWC is nowhere near the extravagance of some of the ones I've seen on here, so I know you've all seen it all anyway! I already have some "before" pics of the ski, and have already started some cosmetic changes color-wise that look pretty sharp for what it is. lol.

I will answer some of those questions. Others can chime in with more comments.

Fuel system; 100% must do. No negotiations. It is critical that the fuel system be perfect. Not that hard to do, not that expensive in parts. Piston lean burn is a common failure and almost always caused by fuel system or carb non-maintenance.

Impeller; part number is on the side of the hub. I suppose you could read it with a mirror and some lighting, but it really is not that hard to pull the jet pump off. While the pump is removed you can inspect and grease the drive splines, check the impeller bearings for smoothness, read the part number, check blade clearances, and so on.

Buy an impeller removal tool, only $10 from Overtons, a bit more from John Zigler (who has lots of other good stuff, new and used). You don't need the tool right away to do the above inspections, but when it comes time to change the impeller or rebuild the jet pump you will need it.

Intake grates; the R&D '650' or '750SL' intake grates are good choices for moderate chop riding.

Pump wedges; see my signature links for lots more info on jet pumps and much more.

Gasoline; with ethanol blend or other oxygenates Polaris recommended 89 octane. 87 octane is the absolute minimum octane. I run 91 octane in my newer engines mostly because that is the only fuel grade I can purchase in my area WITHOUT ethanol.

Ethanol in gasoline does no favors for watercraft engines. They can put up with it, but again maintenance of the fuel system is critical.

Jetworks valves restrict water flow into the exhaust at low RPM. This improves initial acceleration from idle but there is a risk of exhaust system overheat if the engine is operated at low speed for too long. How long is too long? Depends, but frequent burps of the throttle to push water through the Jetworks valve will maintain the minimum required exhaust system cooling.

I would not put one in my own watercraft as I often ride through low speed channels and need to the exhaust system to stay cool without pulsing the throttle every minute.

Maintenance; the only thing that will make your fifteen year old machine reliable is the effort you put into maintaining it. These machines do not respond well to the 'wait until it fails' approach. See my signature links for more recommended maintenance and common upgrades.

* I read that these older ski's should have the fuel system checked over and most likely have the lines and such replaced. They appear to be in great shape, although I don't know about the insides. The ski's been sitting for a year and a half until we fixed it and fired it, and test rode it this weekend, so is there anything else I should upgrade right off the top? Should I invest in new lines anyway??

If the lines are original equipment they need to be redone. On my first ski several BROKE OFF at the fittings when I was removing them. Can you say sucking air? On the second ski some were cranked by Hercules himself, again, potential for failure. If you redo the oil lines, the tygon stuff on ebay is very nice.

* I'm aware that this ski came with a 15/20 swirl stock impeller. My buddy said he put a new impeller in it before the old owner ditched the effort, but he can't remember what it was. Can the numbers be taken from the impeller from the underside or somewhere without removing it?? I'm also a little bit stockier rider than most at 250 pounds. The "Dream-o-meter" topped out at 46.8 mph the other day on our lake in some pretty damn choppy water right before a storm. Is that about right for my size and those conditions? What can I expect in calmer water?? Should an impeller pitch change be in the forecast for me after other planned mods??

My skis both get right at 50mph (GPS) flat out on glass. Stock impeller. A different pitch may make it faster, at the expense of hole-shot. I agree the pump ought to get yanked and looked thru anyway.

* I've read that my 3-seater already has a half decent ride plate underneath it (I'm assuming). Although reading that aftermarket plates are scarce for my ski, would an aftermarket ride plate such as the ocean pro be beneficial for me?? As far as my riding conditions, they'll most likely always be at our lake (Lake Anna, VA). It stays pretty choppy, but not too overly rough due to alot of recreational traffic, although if you go to the other side of the lake which I do sometimes, you might catch a calm day out of a few. Just depends on when I feel like alternating between the hot and cold sides of the lake.

My brother had some smaller Yamaha's, and he says the 780s I have are VERY stable compared to his.

* As far as intake grates, I'm reading that most of you are using an R&D or an Ocean pro for different reasons. I don't plan on being much of a trick rider or doing outrageous maneuvers with this thing, at least not anytime soon, and am really more-so concerned about getting as much speed out of this thing that I can. I drag race cars with most of my time, so what can i say, I'm addicted lol. To answer another question that may pop up, I'll rarely have anybody else on the ski with me, maybe a girl here or there , and the most that would happen would be pulling a smaller 1 person tube with a 90 pound kid on it, so that's the extent of it, mainly just me 95% of the time.

No idea, mine are stock.

* I read a thread on the SBT forums about some people recommending changing the wedge to a 6 degree (I guess mine is 4 degrees??) and getting extended pumps. What the hell are they talking about, and what would I have right now?? What would you guys recommend???

I have considered this also, but not sure it is worth the 2-3mph it might yield. I also have been considering adding trim to at least one of mine just as a test to see what it adds to the speed.

* As far as gasoline, are most of you guys running 93 octane?? Is that whats recommended in these things??

I run 93, but only cause I love my skis and I am worried one of them may have a bit of a detonation issue I am still trying to solve.

* I think I'd like to change the reeds soon. Been looking at the Boyesen Pro Series reeds ( not the racing ones). Would this be a decent choice for what I'm looking for? (I don't see those V-Force's or the Boyesen Rad valves in my budget at this time lol).. If I put these reeds in, will I need to re-jet the carbs a huge amount?? If so, where can I acquire the needed jet kit for this?? Should I look into aftermarket reed cages if there are any?? Would the reed spacers be a good investment along with the other things??

I'd be interested in how changing reeds affects performance. RKI's?

* What is this "jetworks valve" that others have spoken of? Is it an upgrade and/or a necessity?

No idea.

* I know they're pricey, but would the 785 Pro CDI be beneficial to me in the long run?? Does it require any major changes in the ski?

Sounds like a trip down the tuning/timing rabbit-hole to me.

* Although I don't think I'm interested in the modifications (right now) required to install those "triple pipes" on this thing, I wouldn't mind having some kind of aftermarket exhaust. What are these "short pipes"?? Are they worth it, and if so, are they readily available anywhere??

I assume these are individual exhausts for the three cylinders, but not sure.

As a fellow drag racer I'll put my minimum Polaris knowledge into this.. I have 2 1995 Polaris SL 750.
The one I first got had the motor pulled and needed a stator. The gentleman I purchased it from had it bored out and wiseco piston upgraded. He upgraded the fuel lines and oil lines to a minimum. I put it all together and took it for a spin just to see how it ran.. For me it was great. kind of like high school bracket racing your street car.. I then purchased the triple fuel pump, oil block kit, new fuel lines for the Rail (from the tank to pump were already changed). I premix my gas now.. I can say I could tell the difference in consisitancey. No mixing/ fuel issues at all. Seems the ski actually runs better longer.
Purchased the 2nd SL 750 and it needed a cylinder and piston because of the fuel system wasnt upgraded and he burnt out the cyclinder. So I replaced everything these guys highly recommend and put it together. Still fast and fun but doesnt have as much power from the start as the other one in my opinion.
So what I would recommend depending on how in depth you want to go is doing all the important upgrades to keep your ski maintained and reliable like the fuel system upgrades and carb rebuild kits. Then maybe during the winter if you want to upgrade and go to Bracket 2 style speed, I'd do a Engine upgrade with cylinder bore and Pistons and a aftermarket exhaust/water cooling system. Anything more than that your getting in above my head and might not be worth the investment. Mine runs about 55-58 gps on smooth water about 49-53 on the river which is a little choppy. The factory one runs about 43-46 on the river.. So not that major of a difference on the top end, just gets up quicker to me.. Good luck and have fun riding!!

Hi there fellas. Glad to be apart of this deal yall have going on here. Quite a bit of info I've browsed through in the past week has already been helpful, but I thought I'd try to fetch a little more. I'd rather ask questions and learn rather than be stubborn and screw it all up on my own lol!

Anyways, my buddy had this '97 Polaris SLT 780 w/ trailer sitting in his yard that he had told me he'd acquired for $1 (yes, one dollar!). He had previously had an auto/boat repair shop on our lake, and when they had to move on, the previous owner of the ski wasn't interested in having it fixed. He had damaged the front piston somehow. Long story short, my buddy had no interest in using it either, and the ski is in damn good shape, was very well maintained other than that one piston problem, so we agreed that if I put forth the $$$ to fix it, it was mine. 1 $60 piston and ring set, and top end gaskets, and I have myself a ski that runs like a top! Compression is great all the way through! I apologize before hand for all these questions, but here they come:

* I read that these older ski's should have the fuel system checked over and most likely have the lines and such replaced. They appear to be in great shape, although I don't know about the insides. The ski's been sitting for a year and a half until we fixed it and fired it, and test rode it this weekend, so is there anything else I should upgrade right off the top? Should I invest in new lines anyway??

* I'm aware that this ski came with a 15/20 swirl stock impeller. My buddy said he put a new impeller in it before the old owner ditched the effort, but he can't remember what it was. Can the numbers be taken from the impeller from the underside or somewhere without removing it?? I'm also a little bit stockier rider than most at 250 pounds. The "Dream-o-meter" topped out at 46.8 mph the other day on our lake in some pretty damn choppy water right before a storm. Is that about right for my size and those conditions? What can I expect in calmer water?? Should an impeller pitch change be in the forecast for me after other planned mods??

* I've read that my 3-seater already has a half decent ride plate underneath it (I'm assuming). Although reading that aftermarket plates are scarce for my ski, would an aftermarket ride plate such as the ocean pro be beneficial for me?? As far as my riding conditions, they'll most likely always be at our lake (Lake Anna, VA). It stays pretty choppy, but not too overly rough due to alot of recreational traffic, although if you go to the other side of the lake which I do sometimes, you might catch a calm day out of a few. Just depends on when I feel like alternating between the hot and cold sides of the lake.

* As far as intake grates, I'm reading that most of you are using an R&D or an Ocean pro for different reasons. I don't plan on being much of a trick rider or doing outrageous maneuvers with this thing, at least not anytime soon, and am really more-so concerned about getting as much speed out of this thing that I can. I drag race cars with most of my time, so what can i say, I'm addicted lol. To answer another question that may pop up, I'll rarely have anybody else on the ski with me, maybe a girl here or there , and the most that would happen would be pulling a smaller 1 person tube with a 90 pound kid on it, so that's the extent of it, mainly just me 95% of the time.

* I read a thread on the SBT forums about some people recommending changing the wedge to a 6 degree (I guess mine is 4 degrees??) and getting extended pumps. What the hell are they talking about, and what would I have right now?? What would you guys recommend???

* As far as gasoline, are most of you guys running 93 octane?? Is that whats recommended in these things??

* I think I'd like to change the reeds soon. Been looking at the Boyesen Pro Series reeds ( not the racing ones). Would this be a decent choice for what I'm looking for? (I don't see those V-Force's or the Boyesen Rad valves in my budget at this time lol).. If I put these reeds in, will I need to re-jet the carbs a huge amount?? If so, where can I acquire the needed jet kit for this?? Should I look into aftermarket reed cages if there are any?? Would the reed spacers be a good investment along with the other things??

* What is this "jetworks valve" that others have spoken of? Is it an upgrade and/or a necessity?

* I know they're pricey, but would the 785 Pro CDI be beneficial to me in the long run?? Does it require any major changes in the ski?

* Although I don't think I'm interested in the modifications (right now) required to install those "triple pipes" on this thing, I wouldn't mind having some kind of aftermarket exhaust. What are these "short pipes"?? Are they worth it, and if so, are they readily available anywhere??

*SIGH*

I think that's all I can think of right now. Like I said, I apologize for the length and any rambling. Just trying to learn and have some fun. Any links you guys could provide for anything I mentioned would be greatly appreciated. If you all need to know any more info from my end, that's no problem at all. I'm gonna try to provide some pictures of things as I go along, although my PWC is nowhere near the extravagance of some of the ones I've seen on here, so I know you've all seen it all anyway! I already have some "before" pics of the ski, and have already started some cosmetic changes color-wise that look pretty sharp for what it is. lol.

Thanks alot guys, lookin' forward to hearin' back from yall!

Ryan

Things to skip, 785 CDI, v force reeds, ( tried them,no gain on a 780 $300 mistake) & the short pipe (dry pipe). You already have the extended pump on yours. The ride plate could be changed with the upgraded ones that are on the '99 or later 3 seaters, good for 1mph, same results as the ocean pro, but cheaper & easier to find. 6* wedge will help you out on smoother water, any intake grate made will slow you down on smooth water, I tried several for Polaris models in the '90's, however if you ride in nothing but chop then a grate will help you maintain speed. The stock prop is about as good as it is going to get, provided it & the pump housing are in good condition. The speed you are getting isn't bad being 250 & if you were riding in choppy water, a SLT780 will go 51gps with a 175lb rider in smooth water & low fuel tank. Always use 89 or higher octane if fuel contains ethanol, 87 will bring a swift burndown. This site will keep you going

All the responses are greatly appreciated. You guys are a huge help. I suppose that initial post was a bit long, huh?!? lol. ,y apologies! Anyways, through conversation with my buddy this week, he told me the previous owner/customer had him replace the fuel lines at the same time he replaced the impeller. Whether or not he did all of them remains to be seen. I'm going to go through it this weekend and pull the lines off and inspect them. If I do go with new lines, where do most of you guys get the good quality ones from??

From extended reading, it's sounding more and more like I'll be going with an R&D intake grate. Our lake stays moderately choppy on the weekends when I'll be riding, and is rarely flat unless you're riding on a weekday morning or evening. My question would be, do I go with the "650" or the "sl750" grate? What's the difference?? Does the sl750 "dig" in deeper so to speak?? Also, are they easily removed and installed?? It looks like maybe 1 bolt and some silicone?? Perhaps, if I was certain it was calm out one day, I could swap the stock grate back on with ease??

Are the Boyesen Pro Series reeds a good choice for me?? Do the carbs require extensive re-jetting after the install?? If so, where would I find the jet kit required?? I probably don't need those aftermarket reed spacers since the 780's already have spacers, correct??

I'm a little iffy about that Jetworks valve right now. The only low speed riding I'd be doing is just leaving the no-wake zones, or idling around my buddy's boat when we're out together, but I suppose that's enough to warrant me forgetting to pulse the throttle every minute. We'll see. If I were to get interested in one, where would I find it??

That's all I have for now. Sorry again lol. On a brighter note, my custom seat cover, new hydro-turf, and grips arrived this week. I'll probably be putting all of that on in the garage this weekend, as well as inspecting the fuel system and other items, since it's supposed to rain =(. After I get that stuff on, I'll post up a before and after pic. 'Til then, 'predicate it fellas, and hear back from y'all soon!

If it was mine I would go with the 650 grate, they are very easy to replace on this model, one large phillips screw & a little silicon. For sure skip the jetworks valve on this model, you will melt exhaust hoses, which are no longer made. Boysen reeds may work, I can only say that vforce's do little, slight acceleration gain, but top RPM EXACTLY the same as stock reeds. If you can post a picture of your ski when you get your new seat cover & pads on.

Went ahead and ordered the R&D 650 grate. Sounds like it's gonna be the best choice for my ski, other than maybe putting the stock one back on if I catch a weekend of calmness. Going through the fuel lines today, and if they don't check out, they'll be my next acquisition, followed by the Boyesen Pro Series reeds, and the OP ride plate at some point.

What's the deal with those SS 6 vane pump stators some of you all have?? I understand the concept, but are they worth it?? Also, as I was looking through Skat Trak's website, I browsed through impellers as well. For whatever reason, they recommend their 13/18 swirl as a stock replacement for my 15/20, and either the 13/18 or 14/19 for a limited. I didn't bother looking at why modified would be. Why is this though?? Something to do with their 3-blade design instead of 4?? Any of you run into that before??

I reupholstered the seat last night, and am gonna put the hydro-turf mats on today. I'll get those pics afterwards!